1. Field of the Invention
The present invention relates generally to a code read apparatus for reading codes recorded on a recording medium such as paper, and more particularly to a manual scanning code read apparatus for optically reading, by manual scan, code patterns recorded on a recording medium such as paper. Such code patterns are optically readable and represent so-called multimedia information including audio information such as sound and music, video information obtained from a camera, a video apparatus, etc., and digital code data obtained from a personal computer, a word processor, etc. The read code patterns are reproduced as original multimedia information.
2. Description of the Related Art
There is a conventional system for use in reading information recorded on an optical recording medium to thereby reproduce original information.
For example, optical cards and optical (magnetooptical) disks are known as conventional optical recording media. In general, a mechanical scan system, i.e. an automatic scan system, is adopted to scan a detection element over such optical recording media. Specifically, in a system wherein an optical card is used as an optical recording medium, the optical card is reciprocally moved at a predetermined speed, thereby causing the detection element to scan relative to the optical card. In a system wherein an optical (magnetooptical) disk is used, the optical (magnetooptical) disk is rotated at a predetermined speed, thereby causing the detection element to scan.
In general, these conventional detection elements for optical recording media detect an area with a size less than the width of a recording track and less than the interval of recording pits. Specifically, a "point" sensor is moved relative to an optical recording medium to trace the recording track. Thus, "length" information is reproduced as "time" information. In this case, since an error in speed of the optical recording medium is equal to an error in length (interval) of recorded information units, an allowable variation in speed is on the order of several-ten percent or less, The allowable variation, though, depends on variation frequency.
Normally, canceled the speed variation is by adopting a self-clock system in which sync clocks are produced from reproduced data. In fact, however, the degree of allowance is still on the order of several-ten percent.
Accordingly, the optical recording medium must be driven by a servo-controlled driving mechanism, and cannot be driven manually. This results in an increase in cost and size of the apparatus.
On the other hand, a bar-code reader for reading bar codes recorded on a recording medium such as paper is known as a manual scan apparatus. The bar-code reader, too, cannot read bar codes unless the scan speed is within a predetermined range. In addition, since the operator cannot easily make the bar-code reader scan data at a speed within a predetermined speed range, the probability of achieving a successful reading using the manual scan type bar-code reader is not particularly good. Thus, the manual scan type bar-code reader has not been widely accepted in the market.